Plasticizers for plastics

ABSTRACT

The present invention relates to a mixture encompassing at least one plastic A, in particular polyvinyl chloride (PVC), polyvinyl butyral (PVB), or a polysulfide, and at least one polyester B which can be prepared from a dicarboxylic acid I, and from at least one diol II selected from the group consisting of 1,2-propanediol, 1,3-butanediol, and 1,4-butanediol, and from a monocarboxylic acid III, in particular acetic acid, and also to the use of the mixtures of the invention in casings for electrical devices, in kitchen machines, in computer cases, in piping, chemical apparatus, cables, wire sheathing, window profiles, in interior fittings, in vehicle construction and furniture construction, in floorcoverings, for producing medical items, packaging for food or drink, gaskets, sealing compounds, including those for sealed glazing, films, including roofing films, composite films, phonographic disks, synthetic leather, toys, packaging containers, adhesive tape films, clothing, or coatings, or as fibers for fabrics, or as films for laminated safety glass.

The present invention relates to a mixture encompassing at least oneplastic A, in particular polyvinyl chloride (PVC), polyvinyl butyral(PVB), or a polysulfide, and encompassing at least one polyester B whichcan be prepared from a dicarboxylic acid I, and from at least one diolII selected from the group consisting of 1,2-propanediol,1,3-butanediol, and 1,4-butanediol, and from a monocarboxylic acid III.

DE 10128391.1 discloses that dicarboxylic diesters made from adicarboxylic acid and from an alkylene glycol monoether may be used asplasticizer for polyvinyl butyral or a polysulfide.Cyclohexanepolycarboxylic acids or derivatives of these are also used asplasticizers for polyvinyl chloride or polyvinyl acetals, in particularpolyvinyl butyral, as described in DE 10116812.8, for example.

Besides monomeric cyclohexanepolycarboxylic esters, phthalic esters, andadipic esters, there are also various polyesters used as plasticizersfor plastics. Polyester plasticizers are usually prepared by esterifyingpolyhydric alcohols with a polycarboxylic acid. In the case of syntheseswith an excess of alcohol, terminal alcohol groups may optionally becapped with monocarboxylic acids, while in the case of syntheses with anexcess of acid, terminal acid groups may optionally be capped usingmonohydric alcohols.

Polyester plasticizers are used especially when producing films,coatings, profiles, floorcoverings, or cables from plasticized PVC ifthere are relatively high requirements placed upon resistance toextraction, especially to gasoline, oils, and fats, and upon UVresistance, and the volatility of the plasticizer.

GB 1 173 323 describes polyester plasticizers based on adipic acid and1,3-butanediol, and having terminal acid groups capped using2-ethylhexanol, isodecanol, or isohexanol. The polyesters are intendedto be suitable as plasticizers for PVC and in particular to have highresistance to extraction by hexane, kerosene, alkaline solutions, andsoapy water.

U.S. Pat. No. 5,281,647 describes polyester plasticizers prepared byesterifying adipic acid, trimethylpentanediol, and propylene glycol, andhaving terminal acid groups capped using 2-ethylhexanol. The polyestersare intended to be suitable as plasticizers for PVC and rubber and tohave high resistance to extraction by oils or soapy water.

RO 104 737 describes polyester plasticizers based on adipic acid andpropylene glycol and having terminal acid groups capped using2-ethylhexanol. The polyesters are intended to be suitable asplasticizers for PVC and in particular to have good storage stability.

The disadvantages of the plasticizers described in GB 1 173 323, U.S.Pat. No. 5,281,647 and RO 104 737 are first that they do not havesufficiently high compatibility with plastics, in particular with PVC,PVB, and polysulfide, i.e. they exude to a considerable extent duringuse and therefore result in partial loss of the flexibility of theplastic items produced using the polyester plasticizers. Secondly, theirlow-temperature flexibility properties are inadequate, and there aretherefore limitations on the outdoor use of the plastic items producedusing these plasticizers.

It is an object of the present invention, therefore, primarily toprovide mixtures encompassing a plastic, in particular polyvinylchloride (PVC), polyvinyl butyral (PVB), or a polysulfide, andsubstances whose physical and chemical properties make them suitable foruse as plasticizers in plastics and which have good compatibility andwhich give good low-temperature flexibility in plastic items producedusing these plasticizers.

We have found that this object is achieved by means of mixturesencompassing at least one plastic A and at least one polyester B, thepolyester B being preparable from a dicarboxylic acid I, and from atleast one diol II selected from the group consisting of 1,2-propanediol,1,3-butanediol, and 1,4-butanediol, and from a monocarboxylic acid III.

For the purposes of the present invention, a polyester B which can beprepared from a dicarboxylic acid I, and from at least one diol IIselected from the group consisting of 1,2-propanediol, 1,3-butanediol,and 1,4-butanediol, and from a monocarboxylic acid III implies that adicarboxylic acid I is esterified with at least one diol II selectedfrom the group consisting of 1,2-propanediol, 1,3-butanediol, and1,4-butanediol, and that those hydroxyl groups of the diol not linked tothe dicarboxylic acid have been esterified using a monocarboxylic acid.

According to the invention, the polyester B may be prepared using justone diol II selected from the group consisting of 1,2-propanediol,1,3-butanediol, and 1,4-butanediol, or using a mixture made from two ormore of these, or using a mixture made from a diol II selected from thegroup consisting of 1,2-propanediol, 1,3-butanediol, and 1,4-butanediolwith one or more other diols.

According to the invention, dicarboxylic acids I which are particularlysuitable for building the polyester B are aliphatic dicarboxylic acids,preferably aliphatic dicarboxylic acids having from 4 to 9 carbon atoms,such as adipic acid.

In one preferred embodiment, the present invention therefore providesmixtures encompassing at least one plastic A and at least one polyesterB, the dicarboxylic acid I being an aliphatic dicarboxylic acid havingfrom 4 to 9 carbon atoms, preferably adipic acid.

Examples of other diols suitable for building the polyester B of theinvention, besides the at least one diol II selected from the groupconsisting of 1,2-propanediol, 1,3-butanediol, and 1,4-butanediol are1,2-ethanediol, 1,3-propanediol, 1,2-butanediol, 1,2-pentanediol,1,3-pentanediol, 2-methyl-1,3-pentanediol, 1,4-pentanediol,1,5-pentanediol, neopentyl glycol, 1,2-hexanediol, 1,3-hexanediol,1,4-hexanediol, 1,5-hexanediol, 1,6-hexanediol, diethylene glycol,triethylene glycol, the mononeopentyl glycol ester of hydroxypivalicacid, and mixtures of these diols.

According to the invention, examples of particularly suitablemonocarboxylic acids III are acetic acid, propionic acid,2-ethylhexanoic acid, n-heptanoic acid, and benzoic acid. For thepurposes of the present invention, acetic acid is particularly preferredas monocarboxylic acid III.

The polyester plasticizers of the invention are prepared in a mannerwhich is known per se in industry, by esterifying the dicarboxylic acidI with at least one diol II selected from the group consisting of1,2-propanediol, 1,3-butanediol, and 1,4-butanediol, and, whereappropriate, with other diols, in the presence of a monocarboxylic acidIII for capping groups. The addition of monocarboxylic acid III controlsthe chain length and, respectively, the average molecular weight of thepolyester plasticizers.

In one preferred embodiment, for example, adipic acid and at least onediol selected from the group consisting of 1,2-propanediol,1,3-butanediol, and 1,4-butanediol form an initial charge in a reactionvessel together with, where appropriate, other diols, and acetic acid,and also esterification catalysts, such as dialkyl titanates,methanesulfonic acid, or sulfuric acid, preferably isopropyl butyltitanate, are first heated to 100–140° C. and homogenized by stirring.The reaction mixture is then heated at atmospheric pressure to 160–190°C. Esterification with elimination of water starts at about 150° C. Thewater formed in the reaction is removed by distillation via a column.The reaction mixture is then further heated to 200–250° C., a vacuum of150–300 mbar is applied, and further water produced in the reaction isremoved from the reaction mixture by passage of nitrogen therethrough.The reaction mixture is stirred under vacuum with passage of nitrogen at200–250° C. until the acid value of the reaction mixture has reached avalue of <15 mg KOH/g.

To esterify the free hydroxyl groups, the reaction mixture is thenpreferably pumped into a second vessel and stirred at 200–250° C. undera vacuum of from 10 to 150 mbar, with removal of residual water bypassing nitrogen at an increased rate, until the acid value of thereaction mixture has reached a value of <1.0 mg KOH/g. The product fromthe reaction is then preferably filtered while still at 100–140° C.

The polyesters B of the invention are composed of from 35 to 50 mol % ofdicarboxylic acid I, in particular adipic acid, preferably from 40 to 48mol %, particularly preferably from 42 to 46 mol %, from 5 to 50 mol %of at least one diol II selected from the group consisting of1,2-propanediol, 1,3-butanediol, and 1,4-butanediol, preferably from 10to 49 mol %, particularly preferably from 20 to 48 mol %, and, whereappropriate, from 2 to 35 mol % of one or more other diols, preferablyfrom 15 to 30 mol %, particularly preferably from 20 to 28 mol %, andalso from 2 to 20 mol % of monocarboxylic acid III, in particular aceticacid, preferably from 5 to 15 mol %, particularly preferably from 6 to10 mol %, where the total of the mol % values always has to be 100 mol%.

The polyesters B of the invention have a density of from 1.00 to 1.30g/cm³, preferably from 1.10 to 1.20 g/cm³, particularly preferably from1.12 to 1.16 g/cm³, a viscosity of from 500 to 20 000 mPa*s, preferablyfrom 1 500 to 15 000 mPa*s, particularly preferably from 2 000 to 12 000mPa*s, a refractive index n_(D) ²⁰ of from 1.450 to 1.490, preferablyfrom 1.455 to 1.480, particularly preferably from 1.460 to 1.475, and anaverage molecular weight (number-average) determined by GPC of from 500to 15 000, preferably from 1 000 to 10 000, particularly preferably from2 000 to 8 000.

For the purposes of the present invention, an example of the content ofat least one polyester B in the mixtures is from 1 to 50% by weight,preferably from 5 to 40% by weight, in particular from 10 to 30% byweight, based in each case on the entirety of the components.

The polyesters of the invention are suitable as plasticizers forplastics. They have very good compatibility with plastics, in particularwith PVC, PVB, and polysulfide, and they give plastic items producedusing these plasticizers very good low-temperature flexibility.

For the purposes of the present invention, a plasticizer is a substancewhich reduces the hardness of a plastic, in particular of polyvinylchloride, or of polyvinyl butyral, or of a polysulfide, in the mixtureof the invention.

The compatibility of a plasticizer in a plastic is determined by agingthe plasticized plastic at 70° C. and 100% relative humidity for aprolonged period and weighing to determine the weight loss as aconsequence of exudation of the plasticizer after certain intervals.

Particular plastics which have proven to be particularly advantageousfor the mixtures of the invention are polyvinyl butyral, polyvinylchloride, and polysulfides. A preferred embodiment of the presentinvention therefore provides mixtures encompassing at least one plasticA and at least one polyester B, the plastic A having been selected fromthe group consisting of polyvinyl butyral, polyvinyl chloride, andpolysulfide.

The present invention therefore also provides the use, as plasticizerfor polyvinyl butyral, polyvinyl chloride, or polysulfide, of apolyester B which can be prepared from a dicarboxylic acid I, and fromat least one diol II selected from the group consisting of1,2-propanediol, 1,3-butanediol, and 1,4-butanediol, and from amonocarboxylic acid III.

The plastics A preferably present in the mixture of the invention willbe described in more detail below.

Polyvinyl acetals are obtained from polyvinyl alcohol by reaction withaldehydes. Besides cyclic acetal groups, the polyvinyl acetals may alsohave hydroxyl and acetate groups. One way of preparing polyvinyl butyralis reaction of a solution of polyvinyl alcohol in water withbutyraldehyde and acid. In this process the PVB obtained precipitatesfrom the solution.

Polyvinyl butyral is in particular prepared in a three-stage process viapolyvinyl alcohol, starting from acetylene and acetic acid to preparevinyl acetate monomer. Since vinyl alcohol is not a stable free compoundand is not available for polymerization, the polyvinyl acetate ishydrolyzed in the presence of methanol to give polyvinyl alcohol.Polyvinyl butyral is obtained by acetalizing the polyvinyl alcohol withbutyraldehyde in an acidic medium. Examples of ways of obtainingvariants of the PVB resin are by way of the selection of the molecularweight of the starting polyvinyl acetate, the degree of hydrolysis togive polyvinyl alcohol, and the amount of butyraldehyde used foracetalization. PVB may therefore also be regarded as a terpolymer ofvinyl acetate, vinyl alcohol, and vinyl butyral.

The properties of PVB are primarily determined by the proportion of freehydroxyl groups, and this is determined by the degree of hydrolysis ofpolyvinyl acetate to polyvinyl alcohol and by the amount ofbutyraldehyde used during acetalization. The proportion of free hydroxylgroups is generally from 5 to 50%, preferably from 10 to 40%, andparticularly preferably from 15 to 25%.

Depending on the nature and the distribution of the cyclic acetalgroups, hydroxyl groups, and acetate groups, the softening point of thePVB is from 80 to 150° C., in particular from 90 to 140° C.

Polyvinyl butyral is particularly used for producing films. Thethickness of PVB films is typically from 0.1 to 2 mm, in particular from0.4 to 1.5 mm.

A polysulfide is for the purposes of the present invention a polymerwith thioether groups. Polysulfides can be linear or branched or elsecrosslinked. As well as thioether groups, the polysulfides usedaccording to the invention may contain further functional groups in themain or side chains. For the purposes of the present invention, themixtures according to the invention may also comprise two or moredifferent polysulfides.

The polysulfides present in the mixtures of the invention may containother functional groups besides thioether groups, in particular ethergroups, aromatic groups, or else urethane groups. The polysulfides usedaccording to the invention are preferably polymeric alkyl thioethers,and for the purposes of the present invention these alkyl groups may belinear or branched.

Polysulfides are in particular prepared by polycondensing alkali metalpolysulfides, such as sodium pentasulfide, with alkyl dihalides, e.g.1,2-dichloroethane or bis(2-chloroethoxy)methane. Trihalides, e.g.1,2,3-trichloropropane, may also be added for crosslinking.

The properties of the polysulfides are in particular dependent on thenature of the alkyl radical, the sulfur content, and the molar mass, andalso on the crosslinking density of the polysulfide. The molar masses ofthe polysulfides present in the mixtures of the invention are preferablyin the range from 1 000 to 8 000 g/mol. The density of crosslinking, forexample via sulfur bridges through reaction of terminal mercapto groups,affects the hardness of the polysulfides. According to the invention,the crosslinking density is in the range from 0.01 to 10 mol %,preferably from 0.02 to 5 mol %, in particular from 0.05 to 2 mol %.

For the purposes of the present invention, the polysulfides present inthe mixtures of the invention are resistant to temperatures in the rangefrom −50 to 125° C., in particular from −35 to 100° C.

Examples of uses of polysulfides are the production of sealingcompounds, in particular sealing compounds for sealed glazing.

Polyvinyl chloride is obtained by homopolymerizing vinyl chloride.Examples of ways of preparing the polyvinyl chloride (PVC) usedaccording to the invention are suspension polymerization,microsuspension polymerization, emulsion polymerization, and bulkpolymerization. An example of a description of the preparation of PVC bypolymerizing vinyl chloride, and of the preparation and composition ofplasticized PVC is found in “Becker/Braun, Kunststoff-Handbuch, Volume2/1: Polyvinylchlorid”, 2nd Edition, Carl Hanser Verlag, Munich.

Depending on the content of plasticizers, mixtures comprising aplasticizer and polyvinyl chloride are divided into rigid PVC (<0.1% ofplasticizers) and plasticized PVC (>0.1% of plasticizers).

The K value which characterizes the molecular weight of the PVC and isdetermined to DIN 53726 is from 57 to 90 for the PVC used according tothe invention, preferably from 61 to 85, in particular from 64 to 75.

For the purposes of the invention, the content of polyvinyl acetal, inparticular PVB, or of PVC, or, respectively, of a polysulfide, in themixtures is from 20 to 99% by weight, preferably from 45 to 95% byweight, particularly preferably from 50 to 90% by weight, and inparticular from 55 to 85% by weight, based in each case on the entiretyof the components.

Besides at least one plastic A and at least one polyester B, themixtures of the invention may also comprise other suitable additives.Examples which may be mentioned are stabilizers, lubricants, fillers,pigments, flame retardants, light stabilizers, blowing agents, polymericprocessing aids, impact modifiers, optical brighteners, antistats, andbiostabilizers.

Some suitable additives are described in more detail below. However, theexamples listed do not in any way restrict the mixtures of the inventionbut are intended merely for illustration. All content values are % byweight values, based on the entirety of the components.

Stabilizers in particular neutralize the hydrochloric acid evolvedduring and/or after the processing of PVC.

The stabilizers used may be any of the conventional PVC stabilizers insolid or liquid form, for example conventional Ca/Zn stabilizers, Ba/Znstabilizers, Pb stabilizers, or Sn stabilizers, or else acid-bindingphyllosilicates, such as hydrotalcite.

The mixtures of the invention may have a content of from 0.05 to 7%,preferably from 0.1 to 5%, particularly preferably from 0.2 to 4%, andin particular from 0.5 to 3%, of stabilizers, based in each case on theentirety of the components.

Lubricants are intended to act between the particles of the plastic andreduce frictional forces during mixing, plastification, and shaping.

Lubricants which may be present in the mixtures of the invention are anyof the usual lubricants for plastics processing. Examples of those whichmay be used are hydrocarbons, such as oils, paraffins, and PE waxes,fatty alcohols having from 6 to 20 carbon atoms, ketones, carboxylicacids, such as fatty acids or montanic acid, oxidized PE wax, metalcarboxylates, carboxamides, and also carboxylic esters, for example withthe alcohols ethanol, fatty alcohols, glycerol, ethanediol,pentaerythritol, and long-chain carboxylic acids as acid component.

The mixtures of the invention may have a content of from 0.01 to 10% byweight, preferably from 0.05 to 5% by weight, particularly preferablyfrom 0.1 to 3% by weight, and in particular from 0.2 to 2% by weight, oflubricant, based in each case on the entirety of the components.

Fillers affect mainly compressive strength, tensile strength, andflexural strength, and also the hardness and heat resistance ofplasticized plastics, in particular PVC, PVB and plasticizedpolysulfide, this effect being favorable.

For the purposes of the invention, the mixtures may also comprisefillers, for example carbon black and other inorganic fillers, e.g.naturally occurring calcium carbonates, such as chalk, limestone, andmarble, synthetic calcium carbonate, dolomite, silicates, silica, sand,diatomaceous earth, aluminum silicates, such as kaolin, mica, andfeldspar. The fillers used are preferably calcium carbonates, chalk,dolomite, kaolin, silicates, talc, or carbon black.

The mixtures of the invention may have a content of from 0.01 to 80% byweight, preferably from 0.1 to 60% by weight, particularly preferablyfrom 0.5 to 50% by weight, and in particular from 1 to 40% by weight, offillers, based in each case on the entirety of the components.

The mixtures of the invention may also comprise pigments in order toadapt the resultant product to various applications.

For the purposes of the present invention, use may be made of eitherinorganic or organic pigments. Examples of inorganic pigments which maybe used are cadmium pigments, such as CdS, cobalt pigments, such asCoO/Al₂O₃, and chromium pigments, such as Cr₂O₃. Examples of organicpigments which may be used are monoazo pigments, condensed azo pigments,azomethine pigments, anthraquinone pigments, quinacridones,phthalocyanine pigments, dioxazine pigments, and aniline pigments.

The mixtures of the invention may have a content of from 0.01 to 10% byweight, preferably from 0.05 to 5% by weight, particularly preferablyfrom 0.1 to 3% by weight, and in particular from 0.5 to 2% by weight, ofpigments, based in each case on the entirety of the components.

The mixtures of the invention may also comprise flame retardants, toreduce flammability and smoke generation during combustion.

Examples of flame retardants which may be used are antimony trioxide,phosphate esters, chloroparaffin, aluminum hydroxide, boron compounds,molybdenum trioxide, ferrocene, calcium carbonate, and magnesiumcarbonate.

The mixtures of the invention may have a content of from 0.01 to 10% byweight, preferably from 0.1 to 8% by weight, particularly preferablyfrom 0.2 to 5% by weight, and in particular from 0.5 to 3% by weight, offlame retardants, based in each case on the entirety of the components.

The mixtures may also comprise light stabilizers in order to protect theitems produced from the mixture of the invention from surface damage dueto exposure to light.

Examples of compounds which may be used for the purposes of the presentinvention are hydroxybenzophenones and hydroxyphenylbenzotriazoles.

The mixtures of the invention may have a content of from 0.01 to 7% byweight, preferably from 0.1 to 5% by weight, particularly preferablyfrom 0.2 to 4% by weight, and in particular from 0.5 to 3% by weight, oflight stabilizers, based in each case on the entirety of the components.

For the purposes of the present invention, the mixtures of the inventionmay also comprise other plastics selected from the group consisting ofhomo- and copolymers based on ethylene, propylene, butadiene, vinylchloride, vinyl acetate, glycidyl acrylate, glycidyl methacrylate, or onacrylates or methacrylates whose alcohol components are branched orunbranched C1–C10 alcohols, styrene, or acrylonitrile.

Examples which should be mentioned are polyacrylates having identical ordifferent alcohol radicals selected from the group consisting of theC4–C8 alcohols, particularly of butanol, of hexanol, of octanol, and of2-ethylhexanol, polymethyl methacrylate, polyvinyl chloride, methylmethacrylate-butyl acrylate copolymers, methyl methacrylate-butylmethacrylate copolymers, ethylene-vinyl acetate copolymers, chlorinatedpolyethylene, nitrile rubber, acrylonitrile-butadiene-styrenecopolymers, ethylene-propylene copolymers, ethylene-propylene-dienecopolymers, styrene-acrylonitrile copolymers, acrylonitrile-butadienerubber, styrene-butadiene elastomers, and methylmethacrylate-styrene-butadiene copolymers.

The mixtures of the invention encompassing polyvinyl butyral orpolysulfides may in particular also comprise additives which areregulators for adhesion behavior with respect to glass, for examplesodium salts, in particular sodium acetate and sodium lecithin. Otherparticular materials which may be present as additives in the mixturesof the invention encompassing at least one polysulfide, in order toimprove adhesion to specific substrates, are phenolic resins, epoxy- ormercapto-functionalized silanes, and epoxy resins.

The mixtures of the invention encompassing polysulfides may also, forexample, comprise hardeners, such as lead dioxide, calcium peroxide,zinc peroxide, or manganese dioxide.

Due to the high compatibility of the components, i.e. of the plastic Aand the polyester B, the mixtures of the invention are particularlysuitable for producing plasticized plastic items.

The invention therefore also provides the use of a mixture encompassingat least one plastic A, in particular polyvinyl chloride (PVC),polyvinyl butyral (PVB), or a polysulfide, and at least one polyester Bwhich can be prepared from a dicarboxylic acid I, and from at least onediol II selected from the group consisting of 1,2-propanediol,1,3-butanediol, and 1,4-butanediol, and from a monocarboxylic acid III,in casings for electrical devices, such as kitchen machines or computercases, piping, chemical apparatus, cables, wire sheathing, windowprofiles, in interior fittings, in vehicle construction and furnitureconstruction, in floorcoverings, for producing medical items, packagingfor food or drink, gaskets, sealing compounds, including those forsealed glazing, films, including roofing films, composite films, filmsfor laminated safety glass, in particular for the vehicle sector and thearchitectural sector, phonographic disks, synthetic leather, toys,packaging containers, adhesive tape films, clothing, or coatings, or asfibers for fabrics.

The invention also provides articles which comprise a mixtureencompassing at least one plastic A, in particular polyvinyl chloride(PVC), polyvinyl butyral (PVB), or a polysulfide, and at least onepolyester B which can be prepared from a dicarboxylic acid I, and fromat least one diol II selected from the group consisting of1,2-propanediol, 1,3-butanediol, and 1,4-butanediol, and from amonocarboxylic acid III. An example of an article of the invention is acasing for electrical devices, piping, apparatus, a cable, wiresheathing, a window profile, a floorcovering, a medical item, a toy,packaging for food or drink, a gasket, a sealing compound, including onefor sealed glazing, a film, including a roofing film, a composite film,a film for laminated safety glass, in particular for the vehicle sectoror the architectural sector, a phonographic disk, a synthetic leather, apackaging container, an adhesive tape film, clothing, or a coating, or afiber for fabrics.

PVB items, in particular PVB films, produced from the mixtures of theinvention have high strength, very good extensibility, and excellentadhesion to glass surfaces. They therefore permit the production ofhighly flexible films with good transparency and light resistance, andvery good glass adhesion, this being particularly important for use asfilms in producing laminated safety glass.

The strength and extensibility of PVB films is in particular determinedvia their Shore hardness A and D (determination to DIN 53505), theirtensile stress at break (determination to DIN EN ISO 527 Parts 1 and 3),their tensile strain at break (determination to DIN EN ISO 527 Parts 1and 3), and their stress at 100% strain (determination to DIN EN ISO 527Parts 1 and 3).

Polysulfide sealing compounds produced using the mixtures of theinvention, for example, have not only high elasticity and low gaspermeability, but also in particular good weathering resistance, goodchemicals resistance, in particular swelling resistance, and good agingresistance.

The low-temperature flexibility properties of plasticized plastics arepreferably characterized with the aid of cold-crack temperature andtorsional rigidity. The cold-crack temperature is the temperature atwhich a plasticized plastic begins to show visible damage when exposedto mechanical load at low temperature. Cold-crack temperature isdetermined to DIN 53372. Torsional rigidity is the temperature at whicha defined source can twist a plasticized plastic through a particularangle. Torsional rigidity is determined to DIN 53447.

1. A mixture encompassing at least one plastic A selected from the groupconsisting of polyvinyl butyral and polysulfide and at least onepolyester B, the polyester B being preparable from 35 to 50 mol % of adicarboxylic acid I, and from 5 to 50 mol % of at least one diol IIselected from the group consisting of 1,2-propanediol, 1,3-butanediol,and 1,4-butanediol, and from 2 to 20 mol % of acetic acid asmonocarboxylic acid III.
 2. A mixture as claimed in claim 1, wherein thedicarboxylic acid I is an aliphatic dicarboxylic acid having from 4 to 9carbon atoms.
 3. A mixture as claimed in claim 1, wherein thedicarboxylic acid I is adipic acid.
 4. A mixture as claimed in claim 1,comprising other plastics selected from the group consisting of homo-and copolymers based on ethylene, propylene, butadiene, vinyl chloride,vinyl acetate, glycidyl acrylate, glycidyl methacrylate, or on acrylatesor methacrylates whose alcohol components are branched or unbranchedC1–C10 alcohols, styrene, or acrylontrile.
 5. An article comprising amixture as claimed in claim
 1. 6. An article as claimed in claim 5,which is casing for electrical devices or is piping, apparatus, a cable,wire sheathing, a window profile a floor covering, a medical item, atoy, packaging for food or drink, a gasket, a sealing compound,including one for sealed glazing, a film, including a roofing film, acomposite film, a film for laminated safety glass, a phonographic disk,a synthetic leather, a packaging container, an adhesive tape film,clothing, or a coating, or a fiber for fabrics.
 7. A method forpreparing plasticized polyvinyl butyral or polysulfide comprising thestep of adding as plasticizer a polyester B which can be prepared from35 to 50 mol % of a dicarboxylic acid I, and from 5 to 50 mol % of atleast one diol II selected from the group consisting of 1,2-propanediol,1,3-butanediol, and 1,4-butanediol, and from 2 to 20 mol % of aceticacid as monocarboxylic acid III to polyvinyl butyral or polysulfide.